Abstract: Most engineers and even scholars can not fully understand advanced constitutive models, which brings great difficulties to the integration of theory with practice. In this paper, the elastoplastic model SIMSAND for granular material is taken as an example of constitutive models to develop a simple tool for modeling soil tests. Firstly, the development environment of MATLAB GUI is briefly introduced, and then the steps of interface development are described step by step such as overall layout design, control parameter input design, tick box design, result display design, control button design, error or warning prompt design. In order to study and train the readers, three cases are selected to study the conventional undrained triaxial test, the conventional triaxial drained test and the triaxial drained test with constant mean stress. Starting from the plastic multiplier, three key formulas with pseudo codes are derived and presented with modifications. The detailed development process and key source program of this tool platform will help readers to imitate and train, and provide examples and support for research and teaching in practice of constitutive modeling.

Key words: elastoplastic model, granular material, simulator